There have been some approaches taken to estimating travel times on arterial links that include speed versus volume to capacity ratios, but these approaches have lacked the ability to accurately determine in real time what the travel time is on a link. Other approaches use a velocity estimate combined with inductive loop measurements, but have not reached the level of accuracy needed to be trusted in realtime arterial information systems. Methods and apparatus are needed to efficiently match or associate an incoming vehicle signature to an outgoing vehicle signature so that estimates of arterial movement can be effectively and accurately calculated in real time.